1. Field of the Invention
This invention relates to a mechanical heart valve apparatus, more particularly to a mechanical heart valve apparatus having a valve opening and two valve plates synchronously rotatable about a pivot axis for closing and opening the valve opening.
2. Description of the Related Art
U.S. Pat. Nos. 4,078,268 and 4,178,639 disclose conventional mechanical heart valves that include a loop-shaped frame defining a valve opening, and valve plates independently pivoted to the loop-shaped frame for closing and opening the valve opening. The valve plates can be pushed to open by a positive pressure from the blood flow. However, the valve plates may be subjected to different positive pressures from the blood flow, which results in different degrees of opening of the valve plates, respectively. As a consequence, the blood flow cannot smoothly pass through the valve opening, which can result in intermittent regurgitation and increase the working burden on the heart and the chances of damaging the valve plates and hemolysis.